Question: When was Boris Johnson the Member of the 56th  Parliament of the United Kingdom?
Paraphrase: On what date did Boris Johnson the Member of the 56th Parliament of the United Kingdom?
SPARQL (Wikidata): SELECT ?value WHERE { wd:Q180589 p:P39 ?s . ?s ps:P39 wd:Q30524718 . ?s pq:P580 ?value}